1. Field of the Invention
The present invention is generally directed to fittings, components, and associated tools for use in coupling pipe and tubing.
2. General Background of the Invention
Pipe and tubing unions have many applications in fluid handling services. Such applications include potable water applications, such as joining copper tubing together, as well as more hazardous and sophisticated applications, such as joining piping together for hazardous service operations at high pressure.
One type of union that has gained popularity is the hammer union. As shown in FIGS. 1-2, the hammer union has a nut 1 that is disposed around a male sub end 3. The male sub end has a flange 5 that is configured to mate with a female sub end 7. The flange 5 has a diameter that is sufficient to permit the nut 1 to slide over the flange so as to dispose the nut on the male sub end 3. After placing the nut over the male sub end flange 5, a set of segments 9 can be mated together over the male sub end 3, and held in place with snap ring 11. The segments include a lip 13 that prevents the nut from sliding over the male sub end flange 5. Segments are not always used, however, such as where the male sub end flange is large enough to catch the hammer union nut and prevent it from sliding off the end of the male sub end.
Turning now to FIG. 2, after the segments are in place, the nut is tightened by first manually aligning the threads on the nut with the threads on the female sub end 7, and thereafter hitting three tabs on the nut with a sledge hammer until achieving a seal. Once the service application is complete, the pipe can be decoupled, again by use of a sledge hammer to loosen the fitting.
Problems can arise, however, from the use of hammer unions. For example, hammer unions are susceptible to fatigue caused by the repeated hitting of the nut part of the fitting with a sledge hammer. In some instances, the fatigue in the fitting can make it more difficult to form the seal between the male and female sub ends. In other instances, the fatigue can also lead to hairline cracks in the fitting. When leaks occur during operation of a system, a user has a tendency to again hit the hammer union nut with a sledge hammer in order to further tighten the union's seal to stop the leak. Under certain known high pressure oil and gas services, the hit to a fatigued hammer union under service conditions has caused an explosion to occur, which has unfortunately resulted in the death of those around the fitting.
Attempts have been made to overcome these and other deficiencies in hammer unions. For example, U.S. Pat. No. 6,764,109 to Richardson et al. discloses disposition of an o-ring seal between the female and male sub ends of a hammer union, so as to help prevent leakage via compression of the o-ring as the union is tightened.
U.S. Patent Application Serial No. 2015/0226355 to Ungchusri et al. discloses a hammer union that locates a plurality of load segments between a hammer union nut and the male sub end in order to help withstand horizontal loads occurring when the hammer union is assembled, thereby reducing fatigue in the union.
U.S. Pat. No. 6,945,569 to Diaz et al. discloses a hammer union where a segment interfaces with the union's nut and the male sub end flange in a conical arrangement in order to reduce stress in the nut segment so as to prevent deformation of the nut section of the union.
U.S. Pat. No. 9,186,780 to Dumaine et al. and U.S. Patent Application Serial No. 2014/0260817 to Wilson et al. disclose wrenches that can be disposed around the tabs of a hammer union to tighten and loosen the union without imparting the fatigue caused by the use of a sledge hammer.
U.S. Patent Application Serial No. 2008/0136168 to Ungchusri discloses a modified hammer union nut that includes a web having impact holes for receiving a sliding hammer that can be used to tighten and loosen the nut.
U.S. Patent Application Serial No. 2015/0369415 to Bond et al. discloses a restraint system for securing temporary flow lines that contain hammer union fittings. The system includes endless loop slings that are secured to the flow lines in order to arrest movement of the flow lines during a catastrophic failure of the flow line system.
In view of the background in this area, there remain needs for improved and/or alternative fittings, components, and associated tools for use in coupling pipe and tubing. The present invention is addressed to those needs.